JP6691782B2 - Sulfur-containing graphene oxide or sulfur-containing graphene and method for producing the same - Google Patents
Sulfur-containing graphene oxide or sulfur-containing graphene and method for producing the same Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims description 165
- 229910021389 graphene Inorganic materials 0.000 title claims description 162
- 229910052717 sulfur Inorganic materials 0.000 title claims description 114
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- LJGHYPLBDBRCRZ-UHFFFAOYSA-N 3-(3-aminophenyl)sulfonylaniline Chemical compound NC1=CC=CC(S(=O)(=O)C=2C=C(N)C=CC=2)=C1 LJGHYPLBDBRCRZ-UHFFFAOYSA-N 0.000 description 1
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- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 1
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- CCAFPWNGIUBUSD-UHFFFAOYSA-N diethyl sulfoxide Chemical compound CCS(=O)CC CCAFPWNGIUBUSD-UHFFFAOYSA-N 0.000 description 1
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- Carbon And Carbon Compounds (AREA)
Description
本発明は、酸化グラフェン又はグラフェンに硫黄原子がドープされた硫黄含有酸化グラフェン又は硫黄含有グラフェン及びその製造方法に関する。 TECHNICAL FIELD The present invention relates to graphene oxide, graphene oxide containing sulfur in which graphene is doped with sulfur atoms, or graphene containing sulfur, and a method for producing the same.
グラフェンは、ベンゼン環が平面状（又は２次元状）に連なった構造を有しており、その構造に由来して、機械的特性、電気的特性、熱的特性などの種々の特性が優れているため、電気デバイスなどの様々な分野への利用が検討されている。一方、グラフェンは溶媒に対して均一に分散させることが困難であるため、部分的に酸化され、溶媒に対する分散性を改善して利用されることが多い。しかし、酸化グラフェンは、絶縁性であるため、導電性を必要とされる用途では、還元してグラフェンに戻して利用されている。また、近年、キャパシタや二次電池の電極材料、センサーの構成部材では、高度な電気特性が要求されており、高い理論容量を有する硫黄などの原子をドープした炭素材料も求められている。 Graphene has a structure in which benzene rings are connected in a planar shape (or two-dimensional shape), and due to the structure, various characteristics such as mechanical characteristics, electrical characteristics, and thermal characteristics are excellent. Therefore, its application to various fields such as electric devices is being considered. On the other hand, since it is difficult to uniformly disperse graphene in a solvent, it is often partially oxidized and used to improve dispersibility in the solvent. However, since graphene oxide has an insulating property, it is reduced to graphene for use in applications requiring conductivity. Further, in recent years, high electric characteristics have been required for the electrode materials of capacitors and secondary batteries and the constituent members of sensors, and carbon materials doped with atoms such as sulfur having a high theoretical capacity are also required.
ＷＯ２０１３／０８９０２６号パンフレット（特許文献１）には、金属原子と、窒素原子、ホウ素原子、硫黄原子及びリン原子から選択される少なくとも一種の非金属原子とがドープされているグラフェンからなり、ＣｕＫα線を用いてＸ線回折測定して得られる回折強度曲線における（００２）面のピーク強度に対する不活性金属化合物及び金属結晶に由来する最大のピークの強度比が０．１以下である炭素系材料が開示されている。この文献の実施例では、酸化グラフェンに、塩化鉄及びペンタエチレンヘキサミンを担持させた後、アルゴンガス雰囲気下、９００℃で加熱することにより、酸化グラフェンを還元し、窒素及び鉄をドープしている。 WO2013 / 089026 pamphlet (Patent Document 1) includes graphene doped with a metal atom and at least one non-metal atom selected from a nitrogen atom, a boron atom, a sulfur atom and a phosphorus atom, and a CuKα ray. A carbon-based material having an intensity ratio of the maximum peak derived from the inert metal compound and the metal crystal to the peak intensity of the (002) plane in the diffraction intensity curve obtained by X-ray diffraction measurement using 0.1 is 0.1 or less. It is disclosed. In the examples of this document, graphene oxide is loaded with iron chloride and pentaethylenehexamine, and then heated at 900 ° C. in an argon gas atmosphere to reduce the graphene oxide and dope nitrogen and iron. ..
しかし、この文献の方法では、７００℃以上の高温での焼成が必要となる。さらに、窒素以外の原子をドープする方法については記載されていない。 However, the method of this document requires firing at a high temperature of 700 ° C. or higher. Further, it does not describe a method of doping atoms other than nitrogen.
特開２０１３−１３９３７７号公報（特許文献２）には、グラフェン分散液を提供する第一ステップと、硫黄源化合物を前記グラフェン分散液に溶解して混合液を形成する第二ステップと、前記混合液に反応物を添加して、酸化還元反応によって、前記グラフェンの表面に硫黄単体を生成し、硫黄−グラフェン複合材料を形成する第三ステップと、硫黄−グラフェン複合材料を混合液から分離させる第四ステップとを含む硫黄−グラフェン複合材料の製造方法が開示されている。 JP 2013-139377 A (Patent Document 2) discloses a first step of providing a graphene dispersion, a second step of dissolving a sulfur source compound in the graphene dispersion to form a mixture, and the mixing. A third step of adding a reactant to the liquid and generating a simple substance of sulfur on the surface of the graphene by a redox reaction to form a sulfur-graphene composite material and separating the sulfur-graphene composite material from the mixed liquid. A method of making a sulfur-graphene composite material including four steps is disclosed.
しかし、この文献の方法で得られた複合材料では、硫黄単体をグラフェン表面析出させて担持しているため、表面がナノレベルで不均一であり、成形過程などにおいて担持状態も変化する。 However, in the composite material obtained by the method of this document, simple substance of sulfur is deposited on the surface of graphene and carried, so that the surface is non-uniform at the nano level, and the carrying state also changes during the molding process and the like.
特開２０１１−１２６７４２号公報（特許文献３）には、分散媒中に酸化黒鉛が分散してなる第一分散液中の前記酸化黒鉛を薄片化し、薄片化酸化黒鉛が分散してなる第二分散液を製造する工程と、第二分散液に液中プラズマ照射処理を施して薄片化酸化黒鉛を還元する工程とを含む薄片化黒鉛分散液の製造方法が開示されている。 Japanese Unexamined Patent Application Publication No. 2011-126742 (Patent Document 3) discloses a method in which the graphite oxide in a first dispersion liquid in which graphite oxide is dispersed in a dispersion medium is exfoliated, and exfoliated graphite oxide is dispersed in the second. Disclosed is a method for producing an exfoliated graphite dispersion, which includes a step of producing a dispersion and a step of subjecting a second dispersion to an in-liquid plasma irradiation treatment to reduce exfoliated graphite oxide.
しかし、この方法では、還元により酸化黒鉛の導電性は向上するものの、十分ではない。さらに、この文献には、硫黄原子のドープについて記載されていない。 However, this method is not sufficient although the conductivity of graphite oxide is improved by reduction. Furthermore, this document does not describe the doping of sulfur atoms.
従って、本発明の目的は、硫黄原子が化学結合した状態でドープされ、かつ導電性も高い酸化グラフェン又はグラフェン及びその製造方法を提供することにある。 Therefore, an object of the present invention is to provide graphene oxide or graphene which is doped with sulfur atoms chemically bonded and has high conductivity, and a method for producing the same.
本発明の他の目的は、低温で簡便に硫黄原子を酸化グラフェンの表面に均一にドープできる方法を提供することにある。 Another object of the present invention is to provide a method capable of easily and uniformly doping the surface of graphene oxide with sulfur atoms at low temperature.
本発明のさらに他の目的は、硫黄原子の脱離を抑制でき、長期間に亘り導電性を維持できる酸化グラフェン又はグラフェン及びその製造方法を提供することにある。 Still another object of the present invention is to provide graphene oxide or graphene that can suppress the elimination of sulfur atoms and maintain conductivity for a long time, and a method for producing the same.
本発明者らは、前記課題を達成するため鋭意検討した結果、酸化グラフェン及び硫黄含有化合物を含むスラリーを液中プラズマ処理することにより、酸化グラフェンに硫黄原子が化学結合（Ｃ−Ｓ−Ｃ結合、Ｃ−ＳＯＸ−Ｃ結合（式中、Ｘは１又は２である））した状態でドープされ、かつ導電性も高い硫黄含有酸化グラフェンが得られ、さらに還元処理することにより、導電性を向上できることを見出し、本発明を完成した。 The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, when a slurry containing graphene oxide and a sulfur-containing compound is subjected to plasma treatment in liquid, a sulfur atom is chemically bonded (C—S—C bond) to graphene oxide. , C—SO X —C bond (in the formula, X is 1 or 2) and having a high conductivity, sulfur-containing graphene oxide is obtained, and further reduced to reduce the conductivity. The inventors have found that it can be improved and completed the present invention.
すなわち、本発明の硫黄含有酸化グラフェンは、酸化グラフェンに硫黄原子がドープした硫黄含有酸化グラフェンであって、前記硫黄原子は、前記酸化グラフェンを構成する炭素原子と化学結合している。前記硫黄原子の原子割合は、前記酸化グラフェンを構成する炭素原子に対して１〜３０％程度である。本発明の硫黄含有酸化グラフェンは、表面抵抗が１０７Ω／□以下であってもよく、特に、表面抵抗が５０Ω／□以下の導電性グラフェンであってもよい。 That is, the sulfur-containing graphene oxide of the present invention is a sulfur-containing graphene oxide obtained by doping graphene oxide with a sulfur atom, and the sulfur atom is chemically bonded to the carbon atom constituting the graphene oxide. The atomic ratio of the sulfur atoms is about 1 to 30% with respect to the carbon atoms forming the graphene oxide. The sulfur-containing graphene oxide of the present invention may have a surface resistance of 10 7 Ω / □ or less, and particularly may be conductive graphene having a surface resistance of 50 Ω / □ or less.
本発明には、酸化グラフェン及び硫黄含有化合物を含むスラリーを液中プラズマ処理して酸化グラフェンに硫黄原子をドープするドープ工程を含む前記硫黄含有酸化グラフェンの製造方法も含まれる。前記硫黄含有化合物は低分子硫黄含有化合物であってもよい。前記スラリーは水を含んでいてもよい。本発明の製造方法は、硫黄原子がドープした酸化グラフェンを還元する還元工程をさらに含んでいてもよい。前記還元工程において、不活性ガス雰囲気下、硫黄原子がドープした酸化グラフェンを加熱して還元してもよい。 The present invention also includes a method for producing sulfur-containing graphene oxide, which includes a doping step of doping a slurry containing graphene oxide and a sulfur-containing compound with plasma in liquid to dope the graphene oxide with sulfur atoms. The sulfur-containing compound may be a low molecular weight sulfur-containing compound. The slurry may contain water. The production method of the present invention may further include a reduction step of reducing graphene oxide doped with sulfur atoms. In the reducing step, graphene oxide doped with sulfur atoms may be heated and reduced in an inert gas atmosphere.
また、本発明には、グラフェンに硫黄原子がドープした硫黄含有グラフェンであって、前記硫黄原子が、前記グラフェンを構成する炭素原子と化学結合している硫黄含有グラフェンも含まれる。さらに、本発明には、酸化グラフェン及び硫黄含有化合物を含むスラリーを液中プラズマ処理して酸化グラフェンに硫黄原子をドープするドープ工程及び硫黄原子がドープした酸化グラフェンを還元する還元工程を含む前記硫黄含有グラフェンの製造方法も含まれる。 In addition, the present invention also includes sulfur-containing graphene in which graphene is doped with a sulfur atom, and the sulfur atom is chemically bonded to a carbon atom forming the graphene. Furthermore, in the present invention, the sulfur including a doping step of doping a slurry containing graphene oxide and a sulfur-containing compound into a plasma in the liquid to dope the graphene oxide with a sulfur atom and a reducing step of reducing the graphene oxide doped with the sulfur atom. Also included is a method of making contained graphene.
本発明では、酸化グラフェン及び硫黄含有化合物を含むスラリーを液中プラズマ処理して硫黄含有酸化グラフェンを製造しているため、酸化グラフェンに硫黄原子が化学結合（Ｃ−Ｓ−Ｃ結合、Ｃ−ＳＯＸ−Ｃ結合）してドープでき、導電性も向上できる。この方法によると、低温で簡便に硫黄原子を酸化グラフェンの表面に均一にドープできる。さらに、得られた硫黄含有酸化グラフェンを還元することにより、部分的に還元された硫黄含有酸化グラフェン（硫黄含有部分酸化グラフェン）又は硫黄含有グラフェン（以下「硫黄含有（酸化）グラフェン又は導電性グラフェン」と称することもある）を調製でき、さらに導電性を向上できる。これらの硫黄含有（酸化）グラフェンでは、硫黄原子の脱離も抑制でき、長期間に亘り導電性を維持できる。特に、これらの硫黄含有（酸化）グラフェンは、硫黄の導入により、キャパシタや二次電池の電極材料、センサーの構成部材として有効に利用できる。 In the present invention, since a slurry containing graphene oxide and a sulfur-containing compound is plasma-treated in the liquid to produce sulfur-containing graphene oxide, a sulfur atom is chemically bonded to the graphene oxide (C—S—C bond, C—SO bond). It can be doped by ( X— C bond) and conductivity can be improved. According to this method, the surface of graphene oxide can be uniformly doped with sulfur atoms easily at low temperature. Furthermore, by reducing the obtained sulfur-containing graphene oxide, partially reduced sulfur-containing graphene oxide (sulfur-containing partial oxide) or sulfur-containing graphene (hereinafter referred to as “sulfur-containing (oxidized) graphene or conductive graphene”) (Sometimes referred to as)) can be prepared, and the conductivity can be further improved. In these sulfur-containing (oxidized) graphenes, elimination of sulfur atoms can also be suppressed, and conductivity can be maintained for a long period of time. In particular, these sulfur-containing (oxidized) graphenes can be effectively used as an electrode material of capacitors and secondary batteries and a constituent member of sensors by introducing sulfur.
［硫黄含有酸化グラフェン］
本発明の硫黄含有酸化グラフェンは、酸化グラフェンを含む。酸化グラフェンは、天然又は人工グラファイトを酸化し、単層又は多層に剥離させ、単層酸化グラフェン又は多層酸化グラフェンの形態で調製できる。
[Sulfur-containing graphene oxide]
The sulfur-containing graphene oxide of the present invention includes graphene oxide. Graphene oxide can be prepared in the form of single-layer graphene oxide or multi-layer graphene oxide by oxidizing natural or artificial graphite and exfoliating it into a single layer or multiple layers.
グラファイトの酸化は、慣用の方法、例えば、水性媒体中、酸化剤を用いて行うことができる。酸化剤としては、慣用の酸化剤、例えば、硫酸、過マンガン酸塩（過マンガン酸カリウムなど）、クロム酸又は重クロム酸塩（重クロム酸ナトリウムなど）、硝酸塩（硝酸ナトリウムなど）、過酸化物（過酸化水素など）、過硫酸塩（過硫酸アンモニウムなど）、有機過酸（過蟻酸、過酢酸、過安息香酸など）などが例示できる。これらの酸化剤は単独で又は二種以上組み合わせて使用できる。 Oxidation of graphite can be carried out in a conventional manner, for example using an oxidizing agent in an aqueous medium. As the oxidizing agent, a conventional oxidizing agent, for example, sulfuric acid, permanganate (such as potassium permanganate), chromic acid or dichromate (such as sodium dichromate), nitrate (such as sodium nitrate), peroxidation Examples thereof include substances (hydrogen peroxide, etc.), persulfates (ammonium persulfate, etc.), organic peracids (performic acid, peracetic acid, perbenzoic acid, etc.). These oxidizing agents can be used alone or in combination of two or more kinds.
水性溶媒は、水単独、水と水溶性溶媒との混合溶媒であってもよく、水溶性溶媒としては、例えば、メタノール、エタノール、イソプロパノールなどのアルコール類、アセトンなどのケトン類、ジオキサン、テトラヒドロフランなどのエーテル類、セロソルブ類、セロソルブアセテート類、カルビトール類、カルビトールアセテート類、ニトリル類（アセトニトリルなど）、アミド類（Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミドなど）などが例示できる。なお、水性溶媒は、水を主成分（例えば、水含有量５０〜１００重量％程度）とする溶媒であってもよい。 The aqueous solvent may be water alone or a mixed solvent of water and a water-soluble solvent, and examples of the water-soluble solvent include alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, dioxane and tetrahydrofuran. And ethers, cellosolves, cellosolve acetates, carbitols, carbitol acetates, nitriles (acetonitrile etc.), amides (N, N-dimethylformamide, N, N-dimethylacetamide etc.) and the like. The aqueous solvent may be a solvent containing water as a main component (for example, water content of about 50 to 100% by weight).
これらの酸化剤のうち、酸化能の高い酸化剤、例えば、過マンガン酸塩、過硫酸塩などを用いる場合が多い。 Of these oxidizing agents, an oxidizing agent having a high oxidizing ability, such as permanganate or persulfate, is often used.
酸化剤の使用量は、グラファイトの酸化度に応じて選択でき、例えば、グラファイトの炭素原子１モルに対して、０．５〜５モル、好ましくは０．７〜２モル、さらに好ましくは０．９〜１．５モル（例えば、１〜１．２モル）程度であってもよい。 The amount of the oxidizing agent to be used can be selected according to the degree of oxidation of graphite, and for example, is 0.5 to 5 mol, preferably 0.7 to 2 mol, and more preferably 0. It may be about 9 to 1.5 mol (for example, 1 to 1.2 mol).
酸化反応は、酸化剤の存在下、グラファイトが分散した水性媒体中、例えば２０〜１００℃、好ましくは３０〜７５℃、さらに好ましくは４０〜６０℃程度の温度で行うことができる。なお、反応は撹拌下で行うことができ、通常、大気又は空気中、必要であれば、不活性雰囲気中で行ってもよい。 The oxidation reaction can be carried out in the presence of an oxidizing agent in an aqueous medium in which graphite is dispersed, for example, at a temperature of about 20 to 100 ° C, preferably 30 to 75 ° C, more preferably about 40 to 60 ° C. The reaction can be carried out under stirring, usually in the atmosphere or air, and if necessary, in an inert atmosphere.
酸化反応の後、生成した水性分散液を超音波処理して単層又は多層に剥離させ、単層酸化グラフェン又は多層酸化グラフェンを調製できる。なお、必要であれば、遠心分離により、単層酸化グラフェンを多層酸化グラフェン（２層酸化グラフェン、３層酸化グラフェンなどの多層酸化グラフェン）と分離してもよい。 After the oxidation reaction, the generated aqueous dispersion is subjected to ultrasonic treatment to be exfoliated into a single layer or multiple layers, whereby single-layer graphene oxide or multi-layer graphene oxide can be prepared. Note that, if necessary, the single-layer graphene oxide may be separated from the multi-layer graphene oxide (multi-layer graphene oxide such as bilayer graphene oxide and trilayer graphene oxide) by centrifugation.
前記酸化反応により、酸化グラフェンには、カルボニル基、ホルミル基、ヒドロキシル基、カルボキシル基、エポキシ基などの酸素含有官能基が生成してもよい。 Oxygen-containing functional groups such as a carbonyl group, a formyl group, a hydroxyl group, a carboxyl group, and an epoxy group may be generated in graphene oxide by the oxidation reaction.
本発明の硫黄含有酸化グラフェンにおいて、酸化グラフェンは、後述するように、還元処理により部分的に還元されたグラフェン（部分酸化グラフェン）であってもよい。酸化グラフェンを還元することにより、導電性をさらに向上でき、導電性グラフェンを調製できる。 In the sulfur-containing graphene oxide of the present invention, the graphene oxide may be graphene partially reduced by the reduction treatment (partial oxide graphene), as described below. By reducing the graphene oxide, the conductivity can be further improved, and the conductive graphene can be prepared.
本発明の硫黄含有酸化グラフェンにおいて、酸化グラフェンには、硫黄原子がドープされている。特に、本発明の硫黄含有酸化グラフェンにおいて、硫黄原子は、前記酸化グラフェンを構成する炭素原子と化学結合又は共有結合（Ｃ−Ｓ−Ｃ結合、Ｃ−ＳＯＸ−Ｃ結合）しているため、前記酸化グラフェンの表面に均一に硫黄原子をドープでき、導電性を向上できるとともに、硫黄原子の脱離も抑制できる。 In the sulfur-containing graphene oxide of the present invention, the graphene oxide is doped with a sulfur atom. In particular, in the sulfur-containing graphene oxide of the present invention, the sulfur atom is chemically bonded or covalently bonded (C—S—C bond, C—SO X —C bond) to the carbon atom forming the graphene oxide, The surface of the graphene oxide can be uniformly doped with sulfur atoms, which can improve the conductivity and suppress the desorption of sulfur atoms.
［硫黄含有グラフェン］
本発明の硫黄含有グラフェンは、還元処理により完全に還元されており、グラフェンに硫黄原子がドープされている。硫黄含有グラフェンにおいても、硫黄原子は、前記グラフェンを構成する炭素原子と化学結合又は共有結合（Ｃ−Ｓ−Ｃ結合、Ｃ−ＳＯＸ−Ｃ結合）しているため、前記グラフェンの表面に均一に硫黄原子をドープでき、導電性を向上できるとともに、硫黄原子の脱離も抑制できる。
[Sulfur-containing graphene]
The sulfur-containing graphene of the present invention is completely reduced by the reduction treatment, and the graphene is doped with sulfur atoms. Also in the sulfur-containing graphene, since the sulfur atom is chemically bonded or covalently bonded (C—S—C bond, C—SO X —C bond) to the carbon atom that constitutes the graphene, it is uniform on the surface of the graphene. Can be doped with a sulfur atom to improve conductivity, and also desorption of a sulfur atom can be suppressed.
［硫黄含有（酸化）グラフェンの特性］
本発明の硫黄含有酸化グラフェンのうち、還元処理されていない硫黄含有酸化グラフェンにおいて、硫黄原子の原子割合は、酸化グラフェンを構成する炭素原子に対して１〜１５％であってもよく、例えば１．５〜１０％、好ましくは２〜５％、さらに好ましくは３〜５％程度である。硫黄原子の割合が少なすぎると、導電性が低下する虞があり、多すぎると、製造が困難となる虞がある。
[Characteristics of sulfur-containing (oxidized) graphene]
Among the sulfur-containing graphene oxides of the present invention, in the sulfur-containing graphene oxide that has not been subjected to the reduction treatment, the atomic ratio of sulfur atoms may be 1 to 15% with respect to the carbon atoms constituting the graphene oxide, for example, 1 0.5 to 10%, preferably 2 to 5%, more preferably 3 to 5%. If the proportion of sulfur atoms is too small, the conductivity may decrease, and if it is too large, the production may become difficult.
還元処理された硫黄含有（酸化）グラフェン（導電性グラフェン）において、硫黄原子の原子割合は、酸化グラフェン（又はグラフェン）を構成する炭素原子に対して１〜３０％であってもよく、例えば２〜２５％、好ましくは３〜２０％、さらに好ましくは３．５〜１５％（特に４〜１０％）程度である。硫黄原子の割合が少なすぎると、導電性が低下する虞があり、多すぎると、製造が困難となる虞がある。 In the reduction-treated sulfur-containing (oxidized) graphene (conductive graphene), the atomic ratio of sulfur atoms may be 1 to 30% with respect to the carbon atoms constituting the graphene oxide (or graphene), for example, 2 -25%, preferably 3-20%, more preferably 3.5-15% (particularly 4-10%). If the proportion of sulfur atoms is too small, the conductivity may decrease, and if it is too large, the production may become difficult.
なお、本発明では、硫黄原子の割合は、Ｘ線光電子分光法（ＸＰＳ：X-ray Photoelectron Spectroscopy）や元素分析（ＣＨＮＯ）により測定された硫黄元素の含有量で規定される。 In the present invention, the proportion of sulfur atoms is defined by the content of sulfur element measured by X-ray Photoelectron Spectroscopy (XPS) or elemental analysis (CHNO).
本発明の硫黄含有（酸化）グラフェンは、硫黄原子がドープされていればよく、還元処理されていない硫黄含有酸化グラフェンであってもよいが、導電性を向上できる点から、還元処理された硫黄含有（酸化）グラフェンが好ましい。還元処理されていない硫黄含有（酸化）グラフェンの酸化度は７０重量％以下であればよく、例えば１〜６０重量％（例えば５〜６０重量％）、好ましくは１〜４０重量％、さらに好ましくは１〜３０重量％程度である。酸化度が大きすぎると、導電性が低下する虞がある。 The sulfur-containing (oxidized) graphene of the present invention may be sulfur-containing graphene oxide that has not been subjected to reduction treatment as long as it is doped with a sulfur atom, but from the viewpoint that conductivity can be improved, the reduced sulfur Contained (oxidized) graphene is preferred. The degree of oxidation of the sulfur-containing (oxidized) graphene that has not been subjected to reduction treatment may be 70% by weight or less, for example, 1 to 60% by weight (for example, 5 to 60% by weight), preferably 1 to 40% by weight, and further preferably It is about 1 to 30% by weight. If the degree of oxidation is too large, the conductivity may decrease.
本発明の硫黄含有（酸化）グラフェンの表面抵抗は１×１０７Ω／□以下（例えば５Ω／□〜１×１０７Ω／□）であり、特に還元処理されていない硫黄含有酸化グラフェンの表面抵抗は１×１０６Ω／□以下（例えば５Ω／□〜１×１０６Ω／□）であってもよく、例えば１×１０５Ω／□以下、好ましくは５×１０４Ω／□以下、さらに好ましくは１×１０４Ω／□以下（特に５×１０３Ω／□以下）であってもよい。 The surface resistance of the sulfur-containing (oxidized) graphene of the present invention is 1 × 10 7 Ω / □ or less (for example, 5Ω / □ to 1 × 10 7 Ω / □), and the surface of the sulfur-containing graphene oxide that has not been subjected to the reduction treatment is particularly preferable. The resistance may be 1 × 10 6 Ω / □ or less (for example, 5 Ω / □ to 1 × 10 6 Ω / □), for example, 1 × 10 5 Ω / □ or less, preferably 5 × 10 4 Ω / □ or less. And more preferably 1 × 10 4 Ω / □ or less (particularly 5 × 10 3 Ω / □ or less).
還元処理された硫黄含有（酸化）グラフェンの表面抵抗は５０Ω／□以下であってもよく、例えば１〜４０Ω／□、好ましくは２〜３０Ω／□、さらに好ましくは３〜２０Ω／□（特に５〜１０Ω／□）程度であってもよい。 The surface resistance of the reduced sulfur-containing (oxidized) graphene may be 50 Ω / □ or less, for example, 1 to 40 Ω / □, preferably 2 to 30 Ω / □, more preferably 3 to 20 Ω / □ (particularly 5 It may be about 10 Ω / □).
硫黄含有（酸化）グラフェンの厚みは、ナノメータサイズ、例えば１〜１００ｎｍ、好ましくは１．５〜５０ｎｍ（例えば１．８〜３０ｎｍ）、さらに好ましくは１．５〜１０ｎｍ（例えば１．８〜５ｎｍ）程度であってもよく、原子１層の厚み又は複数層（例えば２〜１０層、特に２〜５層程度）の厚みを有していてもよい。硫黄含有（酸化）グラフェンは、炭素原子１個の厚みを有する単層構造であってもよく、複数の単層硫黄含有（酸化）グラフェンが所定の間隔で重なり合った多層（例えば２〜１０層、好ましくは２〜５層）構造であってもよい。 The thickness of the sulfur-containing (oxidized) graphene has a nanometer size, for example, 1 to 100 nm, preferably 1.5 to 50 nm (for example 1.8 to 30 nm), and more preferably 1.5 to 10 nm (for example 1.8 to 5 nm). It may have a thickness of one atomic layer or a plurality of layers (for example, 2 to 10 layers, particularly 2 to 5 layers). The sulfur-containing (oxidized) graphene may have a single-layer structure having a thickness of one carbon atom, and a plurality of single-layer sulfur-containing (oxidized) graphenes may be stacked at a predetermined interval (for example, 2 to 10 layers, It may have a structure of preferably 2 to 5 layers).
硫黄含有（酸化）グラフェンの面方向の平均径は、０．１〜１０００μｍ程度の範囲から選択してもよく、例えば１〜５００μｍ（例えば５〜３００μｍ）、好ましくは５〜１００μｍ（例えば１０〜１００μｍ）程度であり、５〜５０μｍ（例えば１０〜３０μｍ）程度であってもよい。なお、硫黄含有（酸化）グラフェンの厚みの測定には、電子顕微鏡、顕微ラマン分光器、原子間力顕微鏡などが利用でき、硫黄含有（酸化）グラフェンの平均径の測定には、電子顕微鏡、光学顕微鏡などが利用できる。なお、異形の硫黄含有（酸化）グラフェンにおいて、平均径は、各導電性グラフェンについて長軸径と短軸径との平均値を算出し、１００個程度の導電性グラフェンの平均値について加算平均することにより算出できる。 The average diameter in the plane direction of the sulfur-containing (oxidized) graphene may be selected from the range of about 0.1 to 1000 μm, for example, 1 to 500 μm (for example, 5 to 300 μm), preferably 5 to 100 μm (for example, 10 to 100 μm). ), And may be about 5 to 50 μm (for example, 10 to 30 μm). Note that an electron microscope, a Raman microscope, an atomic force microscope, or the like can be used to measure the thickness of sulfur-containing (oxidized) graphene, and an electron microscope or an optical microscope can be used to measure the average diameter of the sulfur-containing (oxidized) graphene. A microscope can be used. In addition, in the heteromorphic sulfur-containing (oxidized) graphene, for the average diameter, the average value of the major axis diameter and the minor axis diameter of each conductive graphene is calculated, and the average value of about 100 conductive graphenes is added and averaged. It can be calculated by
［硫黄含有（酸化）グラフェンの製造方法］
本発明の硫黄含有酸化グラフェンは、酸化グラフェン及び硫黄含有化合物を含むスラリーを液中プラズマ（ソリューションプラズマ）処理して酸化グラフェンに硫黄原子をドープするドープ工程を経て得られる。
[Method for producing sulfur-containing (oxidized) graphene]
The sulfur-containing graphene oxide of the present invention is obtained through a doping process in which a slurry containing graphene oxide and a sulfur-containing compound is subjected to in-liquid plasma (solution plasma) to dope the graphene oxide with sulfur atoms.
ドープ工程において、硫黄含有化合物としては、高分子化合物であってもよいが、硫黄原子のドープのし易さの点から、低分子化合物が好ましい。 In the dope step, the sulfur-containing compound may be a high molecular compound, but a low molecular compound is preferable from the viewpoint of easy doping of sulfur atoms.
低分子硫黄含有化合物としては、例えば、無機硫黄含有化合物（硫酸、硫化水素、二酸化硫黄など）、有機硫黄含有化合物（メタンチオールなどのチオール類、ジメチルスルフィドやメチオニンなどのスルフィド類、メルカプト酢酸などのメルカプトカルボン酸、メタンスルホン酸などのアルカンスルホン酸、トルエンスルホン酸などのアリールスルホン酸、ジメチルスルホキシドなどのアルキルスルホキシド類、チオ尿素などのチオ尿素類など）などが挙げられる。これらの低分子硫黄含有化合物は、単独で又は二種以上組み合わせて使用できる。 Examples of the low-molecular-weight sulfur-containing compound include inorganic sulfur-containing compounds (sulfuric acid, hydrogen sulfide, sulfur dioxide, etc.), organic sulfur-containing compounds (thiols such as methanethiol, sulfides such as dimethyl sulfide and methionine, mercaptoacetic acid, etc. Mercaptocarboxylic acid, alkanesulfonic acid such as methanesulfonic acid, arylsulfonic acid such as toluenesulfonic acid, alkylsulfoxides such as dimethylsulfoxide, thioureas such as thiourea) and the like. These low molecular sulfur-containing compounds can be used alone or in combination of two or more.
これらの低分子硫黄含有化合物のうち、取り扱い性などの点から、アルキルスルホキシド類が好ましい。アルキルスルホキシド類としては、例えば、ジメチルスルホキシド（ＤＭＳＯ）、メチルエチルスルホキシド、ジエチルスルホキシドなどのジＣ１−４アルキルスルホキシドなどが挙げられる。これらのアルキルスルホキシド類のうち、硫黄含量が多く、硫黄をドープし易い点から、ＤＭＳＯなどのジＣ１−２アルキルスルホキシド（特にＤＭＳＯ）が特に好ましい。 Among these low-molecular-weight sulfur-containing compounds, alkyl sulfoxides are preferable from the viewpoint of handleability. Examples of the alkyl sulfoxides include diC 1-4 alkyl sulfoxides such as dimethyl sulfoxide (DMSO), methylethyl sulfoxide and diethyl sulfoxide. Among these alkyl sulfoxides, diC 1-2 alkyl sulfoxide (particularly DMSO) such as DMSO is particularly preferable because it has a high sulfur content and is easily doped with sulfur.
硫黄含有化合物の割合は、酸化グラフェン１重量部に対して１重量部以上（例えば１〜１０００重量部）であってもよく、例えば５〜５００重量部、好ましくは１０〜３００重量部、さらに好ましくは１５〜１００重量部（特に２０〜５０重量部）程度である。硫黄含有化合物の割合が少なすぎると、酸化グラフェンにドープできる硫黄原子の割合が低下する虞がある。 The proportion of the sulfur-containing compound may be 1 part by weight or more (for example, 1 to 1000 parts by weight), for example, 5 to 500 parts by weight, preferably 10 to 300 parts by weight, and more preferably 1 part by weight of graphene oxide. Is about 15 to 100 parts by weight (especially 20 to 50 parts by weight). If the proportion of the sulfur-containing compound is too low, the proportion of sulfur atoms that can be doped into graphene oxide may decrease.
スラリーに含まれる溶媒の割合は、硫黄含有化合物１００重量部に対して１０重量部以上（例えば１０〜１００００重量部）であってもよく、例えば１００〜５０００重量部、好ましくは１５０〜１０００重量部、さらに好ましくは２００〜８００重量部（特に３００〜５００重量部）程度である。溶媒の割合が少なすぎると、酸化グラフェンにドープできる硫黄原子の割合が低下する虞がある。 The ratio of the solvent contained in the slurry may be 10 parts by weight or more (for example, 10 to 10000 parts by weight) based on 100 parts by weight of the sulfur-containing compound, for example, 100 to 5000 parts by weight, preferably 150 to 1000 parts by weight. More preferably, it is about 200 to 800 parts by weight (particularly 300 to 500 parts by weight). If the proportion of the solvent is too small, the proportion of sulfur atoms that can be doped into graphene oxide may decrease.
溶媒は、水、有機溶媒のいずれでもよいが、硫黄原子のドープのし易さ、取り扱い性などの点から、水性媒体（例えば、前述のグラファイトの酸化工程で例示された水性媒体など）が好ましく、水が特に好ましい。スラリーは、酸化グラフェンの調製過程で得られた水性分散液であってもよい。 The solvent may be either water or an organic solvent, but an aqueous medium (for example, the aqueous medium exemplified in the above-mentioned graphite oxidation step) is preferable from the viewpoints of easiness of doping with a sulfur atom, handleability, and the like. , Water is particularly preferred. The slurry may be an aqueous dispersion obtained in the process of preparing graphene oxide.
酸化グラフェンの割合は、スラリー全体に対して０．０１重量％以上であればよく、例えば０．０１〜１０重量％、好ましくは０．１〜５重量％、さらに好ましくは０．３〜３重量％（特に０．５〜１重量％）程度である。酸化グラフェンの割合が少なすぎると、生産性が低下する虞がある。 The proportion of graphene oxide may be 0.01% by weight or more with respect to the entire slurry, for example, 0.01 to 10% by weight, preferably 0.1 to 5% by weight, and more preferably 0.3 to 3% by weight. % (Particularly 0.5 to 1% by weight). If the proportion of graphene oxide is too low, the productivity may decrease.
スラリーの液中プラズマ処理としては、慣用の液中プラズマ法（ソリューションプラズマ法）に基づく処理を利用でき、グロー放電によって液体中の気泡の中にプラズマを発生できる方法であれば特に限定ないが、通常、液中パルスプラズマ電源装置から高電圧パルス出力を電極に印加し、電極付近で沸騰した気泡内に液体の沸点以下のプラズマを発生させ、液体からラジカル種を生成する方法を利用できる。液中プラズマ法としては、例えば、特開２０１４−１５２０９５号公報に記載の方法を利用できる。 As the in-liquid plasma treatment of the slurry, a treatment based on a conventional in-liquid plasma method (solution plasma method) can be used, and it is not particularly limited as long as it is a method capable of generating plasma in bubbles in the liquid by glow discharge, Usually, a method of applying a high-voltage pulse output from a submerged pulsed plasma power supply device to an electrode to generate plasma having a boiling point of the liquid or less within the boiling point of the electrode and having a temperature equal to or lower than the boiling point of the liquid to generate a radical species can be used. As the in-liquid plasma method, for example, the method described in JP-A-2014-152095 can be used.
液中プラズマ法は、市販の液中プラズマ装置を用いることができ、端子間距離、端子間印加電圧、周波数、パルス幅などを調整することにより、硫黄原子のドープ率を調整できる。これらの条件は、硫黄含有化合物の種類や割合などに応じて適宜選択できるが、端子間距離は、例えば０．１〜１ｍｍ、好ましくは０．１５〜０．５ｍｍ、さらに好ましくは０．２〜０．４ｍｍ程度であってもよい。端子間印加電圧は、端子間に印加されるプラズマが発生する前の電圧で、例えば２０００〜１００００Ｖ、好ましくは３０００〜９０００Ｖ、さらに好ましくは４０００〜８０００Ｖ程度である。周波数は、例えば１〜３０ｋＨｚ、好ましくは１０〜３０ｋＨｚ、さらに好ましくは２０〜３０ｋＨｚ程度である。パルス幅は、例えば０．１〜４μｓ、好ましくは０．５〜４μｓ、さらに好ましくは１〜４μｓ程度である。処理時間は１分以上（例えば５〜１８０分）であってもよく、通常１０分以上（例えば１０〜２４０分）程度であるが、好ましくは２０分以上（例えば２０〜１８０分）、さらに好ましくは６０分以上（例えば６０〜１２０分）程度あってもよい。 For the in-liquid plasma method, a commercially available in-liquid plasma device can be used, and the doping rate of sulfur atoms can be adjusted by adjusting the distance between terminals, the voltage applied between terminals, the frequency, the pulse width, and the like. These conditions can be appropriately selected according to the type and ratio of the sulfur-containing compound, but the distance between terminals is, for example, 0.1 to 1 mm, preferably 0.15 to 0.5 mm, more preferably 0.2 to It may be about 0.4 mm. The voltage applied between the terminals is a voltage before the plasma applied between the terminals is generated, and is, for example, 2000 to 10000V, preferably 3000 to 9000V, and more preferably 4000 to 8000V. The frequency is, for example, 1 to 30 kHz, preferably 10 to 30 kHz, and more preferably 20 to 30 kHz. The pulse width is, for example, 0.1 to 4 μs, preferably 0.5 to 4 μs, and more preferably 1 to 4 μs. The treatment time may be 1 minute or longer (for example, 5 to 180 minutes), usually about 10 minutes or longer (for example, 10 to 240 minutes), preferably 20 minutes or longer (for example, 20 to 180 minutes), and more preferably May be about 60 minutes or more (for example, 60 to 120 minutes).
このようにして生成した硫黄含有酸化グラフェン（硫黄原子がドープした酸化グラフェン）は、分離精製（例えば、洗浄、遠心分離など）により、回収できる。 The sulfur-containing graphene oxide (graphene oxide doped with a sulfur atom) thus generated can be recovered by separation and purification (eg, washing, centrifugation, etc.).
ドープ工程を経て得られた硫黄含有酸化グラフェンは、さらに還元工程に供して導電性を向上させ、導電性グラフェン（硫黄含有部分酸化グラフェン又は硫黄含有グラフェン）を調製してもよい。 The sulfur-containing graphene oxide obtained through the doping process may be further subjected to a reduction process to improve the conductivity to prepare conductive graphene (sulfur-containing partially oxidized graphene or sulfur-containing graphene).
還元工程では、得られた硫黄含有酸化グラフェンに水性媒体（特に水）を添加してスラリーを調製し、キャストした後、乾燥した薄膜を還元処理に供してもよい。スラリーの濃度は、例えば０．１〜１０重量％（特に１〜５重量％）程度であってもよい。乾燥は、例えば３５〜６０℃（特に４０〜５０℃）程度の温度で加熱してもよく、さらに真空下で加熱してもよい。 In the reduction step, an aqueous medium (particularly water) may be added to the obtained sulfur-containing graphene oxide to prepare a slurry, which may be cast and then the dried thin film may be subjected to a reduction treatment. The concentration of the slurry may be, for example, about 0.1 to 10% by weight (particularly 1 to 5% by weight). Drying may be performed at a temperature of, for example, about 35 to 60 ° C. (particularly 40 to 50 ° C.), and further may be performed under vacuum.
還元工程において、還元方法としては、公知の還元方法、例えば、熱還元法、光還元法、還元剤（ヒドラジン水和物など）を用いる方法、電気化学的還元法などを利用できる。これらの還元方法のうち、熱還元法、光還元法などが汎用され、簡便性などの点から、熱還元法が好ましい。熱還元法では、窒素ガスやアルゴンガスなどの不活性ガス雰囲気下、１００℃以上温度、例えば１００〜３００℃、好ましくは１２０〜２８０℃、さらに好ましくは１５０〜２５０℃（特に１８０〜２２０℃）程度の温度で加熱して還元してもよい。 In the reduction step, as the reduction method, a known reduction method, for example, a thermal reduction method, a photoreduction method, a method using a reducing agent (hydrazine hydrate or the like), an electrochemical reduction method, or the like can be used. Among these reduction methods, the thermal reduction method and the photoreduction method are widely used, and the thermal reduction method is preferable from the viewpoint of simplicity. In the thermal reduction method, under an atmosphere of an inert gas such as nitrogen gas or argon gas, the temperature is 100 ° C or higher, for example, 100 to 300 ° C, preferably 120 to 280 ° C, more preferably 150 to 250 ° C (particularly 180 to 220 ° C). You may heat and reduce at about temperature.
以下に、実施例に基づいて本発明をより詳細に説明するが、本発明はこれらの実施例によって限定されるものではない。なお、実施例及び比較例で得られた導電性グラフェンを以下の項目で評価した。 Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The conductive graphenes obtained in Examples and Comparative Examples were evaluated according to the following items.
［硫黄原子の含有量及び結合状態、酸素原子含有量］
実施例及び比較例で得られた硫黄含有酸化グラフェンの硫黄原子の含有量及び結合状態、酸素原子の含有量については、以下の測定装置を用いて、以下の測定条件で測定した。
[Sulfur atom content and bonding state, oxygen atom content]
The sulfur atom content and bonding state of the sulfur-containing graphene oxides obtained in Examples and Comparative Examples, and the oxygen atom content were measured under the following measurement conditions using the following measurement device.
測定装置：Ｐｈｙｓｉｃａｌ Ｅｃｅｃｔｒｏｎｉｃｓ ＰＨＩ ５８００ ＥＳＣＡ Ｓｙｓｔｅｍ（アルバックファイ社製）
測定条件：Ａｌ Ｍｏｎｏｃｈｒｏｌａｔｅｄ ７ｍｍ ｆｉｌａｍｅｎｔ Ｋα線、絞り８００μｍφ、Ｘ線出力 ３５０Ｗ。
Measuring device: Physical Electronics PHI 5800 ESCA System (manufactured by ULVAC-PHI)
Measurement conditions: Al Monochromated 7 mm filament Kα ray, diaphragm 800 μmφ, X-ray output 350 W.
［表面抵抗］
評価用サンプルをロレスターＧＰ（（株）三菱アナリテック製）を用いて測定した。プローブとしては薄膜測定用のＰＳＰを用いた。
[Surface resistance]
The sample for evaluation was measured using Lorester GP (manufactured by Mitsubishi Analytech Co., Ltd.). As the probe, PSP for thin film measurement was used.
比較例１
（液中プラズマ処理）
イオン交換水２０ｇを、１重量％酸化グラフェンスラリー（（株）ＮＩＳＨＩＮＡ ｍａｔｅｒｉａｌｓ製「ＲａｐＧＯ−１０」）８０ｇと混合攪拌し、液中パルスプラズマ装置（（株）栗田製作所製「ＭＰＰＨＶ０４」）を用いて、表１に示す条件で液中プラズマ処理を行った。反応後の温度は６１℃であった。
Comparative Example 1
(In-liquid plasma treatment)
20 g of ion-exchanged water was mixed with 80 g of a 1 wt% graphene oxide slurry (“RapGO-10” manufactured by NISHINA materials, Inc.) and stirred, and an in-liquid pulse plasma device (“MPPHV04” manufactured by Kurita Manufacturing Co., Ltd.) was used. The in-liquid plasma treatment was performed under the conditions shown in Table 1. The temperature after the reaction was 61 ° C.
（精製スラリーの調製）
得られたプラズマ処理溶液を、遠心分離機（日立工機（株）製「ＣＲ２２Ｎ」）を用いて１０，０００Ｇで５分間遠心処理を行った後、上澄みを除去した。沈殿物にイオン交換水を添加して、再度、遠心処理した。この操作を３回繰り返し、精製スラリーを得た。
(Preparation of refined slurry)
The obtained plasma-treated solution was centrifuged at 10,000 G for 5 minutes using a centrifuge (“CR22N” manufactured by Hitachi Koki Co., Ltd.), and the supernatant was removed. Ion-exchanged water was added to the precipitate, and the mixture was centrifuged again. This operation was repeated 3 times to obtain a purified slurry.
（評価用サンプル作成（還元前／後））
精製スラリーを約２重量％になるように稀釈し、ガラス基板にキャストし、ホットプレートを用いて４５℃で１時間乾燥させた。乾燥後、真空乾燥機を用いて４０℃で１２時間乾燥させた後、さらに窒素雰囲気下で室温から２００℃まで１時間かけて昇温し、還元サンプルを得た。
(Sample preparation for evaluation (before / after reduction))
The purified slurry was diluted to about 2% by weight, cast on a glass substrate, and dried at 45 ° C. for 1 hour using a hot plate. After drying, it was dried at 40 ° C. for 12 hours using a vacuum dryer, and further heated from room temperature to 200 ° C. over 1 hour in a nitrogen atmosphere to obtain a reduced sample.
実施例１
イオン交換水の代わりに、同量のＤＭＳＯ（（株）和光純薬製）を用いて液中プラズマ処理（反応後の温度７１℃）する以外は比較例１と同様にして還元サンプルを得た。
Example 1
A reduced sample was obtained in the same manner as in Comparative Example 1 except that the same amount of DMSO (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of the ion-exchanged water to perform the in-liquid plasma treatment (temperature after reaction 71 ° C.). ..
実施例２
反応時間を３０分から９０分に変更して液中プラズマ処理（反応後の温度８４℃）する以外は実施例１と同様にして還元サンプルを得た。
Example 2
A reduced sample was obtained in the same manner as in Example 1 except that the reaction time was changed from 30 minutes to 90 minutes and the in-liquid plasma treatment (the temperature after the reaction was 84 ° C.) was performed.
実施例及び比較例で得られた還元前／後のサンプルを評価した結果を表１に示す。 Table 1 shows the results of evaluation of the samples before / after reduction obtained in Examples and Comparative Examples.
表１の結果から明らかなように、比較例に比べて、実施例のサンプルは、硫黄ドープ量が多く、導電性も高い。 As is clear from the results in Table 1, the samples of Examples have a large amount of sulfur doping and high conductivity as compared with Comparative Examples.
さらに、図１〜３に、比較例１及び実施例１〜２で得られた酸化グラフェン（還元前）のＸＰＳナロースペクトルを示し、さらに表２〜４に、それぞれの酸化グラフェン（還元前）について、このスペクトルから算出した原子割合及びＳ含有量を示すが、実施例１及び２のサンプルでは、Ｃ−Ｓ−Ｃ結合、Ｃ−ＳＯＸ−Ｃ結合の増加が確認できた。 Further, FIGS. 1 to 3 show XPS narrow spectra of the graphene oxides (before reduction) obtained in Comparative Example 1 and Examples 1 and 2, and Tables 2 to 4 show the respective graphene oxides (before reduction). The atomic ratios and S contents calculated from this spectrum are shown. In the samples of Examples 1 and 2, an increase in C—S—C bonds and C—SO X —C bonds could be confirmed.
本発明の硫黄含有（酸化）グラフェンは、導電材料などのエレクトロニクス材料、リチウムイオン二次電池やキャパシタなどの電極材料（例えば、スーパーキャパシタ、燃料電池用電解質や電極など）、センサー構成部材、導電性断熱体、電磁場シールド材料、プリンター用導電ロール、超伝導電流リードなどの種々の分野に利用できる。 The sulfur-containing (oxidized) graphene of the present invention is used for electronic materials such as conductive materials, electrode materials for lithium ion secondary batteries and capacitors (for example, supercapacitors, fuel cell electrolytes and electrodes), sensor components, and conductive materials. It can be used in various fields such as heat insulators, electromagnetic field shield materials, printer conductive rolls, and superconducting current leads.
Claims (8)
酸化グラフェン及び硫黄含有化合物を含み、かつ前記硫黄含有化合物の割合が前記酸化グラフェン１重量部に対して１重量部以上であるスラリーを液中プラズマ処理して酸化グラフェンに硫黄原子をドープするドープ工程及び硫黄原子がドープした酸化グラフェンを還元する還元工程を含む硫黄含有グラフェンの製造方法。 Sulfur-containing graphene, which is sulfur-containing graphene obtained by doping graphene with a sulfur atom, and in which the sulfur atom is chemically bonded to a carbon atom constituting the graphene and has a surface resistance of 50Ω / □ or less The manufacturing method of
Doping step of doping graphene oxide with sulfur atoms by subjecting a slurry containing graphene oxide and a sulfur-containing compound to a graphene oxide having a ratio of 1 part by weight or more with respect to 1 part by weight of the graphene oxide in liquid plasma and method of manufacturing including sulfur-containing graphene reduction step sulfur atom is reduced graphene oxide doped.
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